Abstract

The concept of reference wavelength is introduced for calibration of a two-color pyrometer. With the reference wavelength method, an analytical formula of the ratio temperature for the two-color pyrometer is derived. A two-color pyrometer is constructed with a silicon photodiode and two narrowband interference filters (12-nm FWHM, 800- and 900-nm peak wavelength). For both channels, the two-color pyrometer is calibrated with the reference wavelength method. The reference wavelengths for the two channels are chosen as 803 and 903 nm, and the correction factors are calculated from the calibration results. In greybody condition which is simulated with a blackbody furnace, the measured temperature error of the two-color pyrometer is less than ±6°C in the temperature range of 700-1000°C. Also measuring surface temperature of an oxidized steel specimen contained in a vacuum furnace, the temperature error is less than ±15°C in the temperature range of 850-1000°C.

© 1989 Optical Society of America